On January 1, 2010, Trent Company granted Dick Williams, an employee, an option to buy 100 shares of Trent Co. stock for $30 per share, the option exercisable for 5 years from date of grant. Using a fair value option pricing model, total compensation expense is determined to be $900. Williams exercised his option on September 1, 2010, and sold his 100 shares on December 1, 2010. Quoted market prices of Trent Co. stock during 2010 were as follows: January 1 $30 per share September 1 $36 per share December 1 $40 per share The service period is for 2 years, beginning January 1, 2010. As a result of the option granted to Williams, using the fair value method, Trent should recognize compensation expense for 2010 on its books in the amount of : a. 1,000 b. 900 c. 450 d. 0